Related to this question, I'm wondering also whether using Vassal on a netbook (=small screen) is a good idea. Are there any tricks helping in such a case, like zooming in/out etc.?
No, using Vassal on a netbook is not a good idea. The standard resolution on most netbooks is 1024x600. While this isn't a bad thing for reading most websites, consuming video, etc. it doesn't work particularly well with the high resolution game boards in Vassal. The problems you will face will differ from module to module, but some of them will be pretty standard.